Precision 3551, charging, using DisplayPort with Thunderbolt 3 USB Type-C

I am considering getting a monitor for my just purchased Precision 3551 workstation.  As best as I can determine, none of the Dell USB Type-C monitors have power supplies sufficient to charge the Precision 3551 via the Thunderbolt 3 USB Type-C port. The only way to transmit DisplayPort protocols from the Precision 3551 is via the USB Type-C cable. But the AC adapter provided with the Precision 3551 also connects via the TB3/USB Type-C port.

Does this mean that if I want to use DisplayPort protocols to transmit to monitors I must acquire a separate 7mm round barrel AC adapter to power the Precision 3551? Because the TB3/USB Type-C port will be occupied providing the display data feed? I don't understand why Dell would make the default charging port for Precision 3551 be the USB Type-C port (even though it has a 7mm charging port) and thus effectively eliminate using that port with their entire family of USB Type-C monitors?  I suppose it drives Thunderbolt docking station sales to overcome this dilemma.

I'd appreciate any recommendations from Precision users that have addressed this issue without a docking station.